Microbiota-derived butyrate potentiates MSLN CAR-T cell therapy by metabolic reprogramming and extracellular matrix remodeling

Despite the success of chimeric antigen receptor (CAR)-T cell therapy in hematologic malignancies, its efficacy in solid tumors remains limited due to T cell dysfunction and immunosuppressive microenvironments. Emerging evidence suggests that gut microbiota-derived metabolites, particularly short-chain fatty acids (SCFAs), may enhance T cell function, but their role in CAR-T therapy is unexplored. Here, in a small patient cohort (n = 4), preliminary metagenomic and metabolomics data suggested an association between higher butyrate levels and improved CAR-T responses, motivating our investigation of sodium butyrate (NaB), a microbiota-derived short-chain fatty acid, as a potential enhancer of CAR-T cell function through integrated metabolic and transcriptional reprogramming. Functional screening showed that NaB treatment augmented CAR-T cell antitumor activity while promoting a memory-like phenotype and reducing exhaustion markers. Mechanistically, NaB amplified antigen-driven phosphorylation of signaling effectors (p-ERK1/2, p-ZAP-70, p-AKT), inducing dual activation of glycolytic and oxidative phosphorylation pathways, coupled with upregulation of extracellular matrix (ECM)-remodeling genes (MMPs, Collagens), thereby improving tumor homing capacity. These preliminary findings suggest NaB as a potential link between microbial metabolism and CAR-T cell efficacy, offering a promising yet exploratory strategy to optimize adoptive immunotherapy through signaling-metabolic-ECM crosstalk, pending validation in larger cohorts.